After a three-week gap, this weekend sees the teams and drivers rev back into action with the first European race of the season in Barcelona. As is customary at this time of year, all of the major players will be bringing serious updates to their cars, so it will be fascinating to see whether there are any changes to the pecking order at a track reckoned to be the best reflection of true form.

Reigning champions Mercedes, of course, have won three of the opening four races, but Ferrari’s victory in Malaysia demonstrated that the Italian team have seriously closed the performance gap, and ever since they have kept the Silver Arrows honest.

The indications from the opening rounds were that Mercedes still have a power and downforce advantage, but Ferrari have superior tyre wear. Will those remain each team’s outstanding characteristics in Barcelona, or will their respective updates change anything significant?

Ferrari’s brilliant strategy in choosing a soft-medium-soft tyre schedule nearly enabled Kimi Raikkonen to score an upset win in Bahrain last time out, as team mate Sebastian Vettel and Mercedes’ drivers Lewis Hamilton and Nico Rosberg opted for soft-soft-medium, and team boss Maurizio Arrivabene plans to maintain that aggressive ploy while Ferrari continue to work on closing the gap.

"In Bahrain we put together an aggressive strategy and this is exactly what we discussed," he says. And he warns: “We now have some solutions for Barcelona. We are doing all of our development step-by-step but I think here we are going to finally take a good package."

Mercedes, however, are determined to weigh up all of their options, rather than just rushing developments through to try and stem the Ferrari tide. Non-executive chairman Niki Lauda says that they won’t be bringing revised engines to this power circuit. "What may appear as a disadvantage now will become an opportunity when it really counts, in the second half of the season," he says. "The right thing to do is to not change work programmes on a whim. In any case, we'll have big changes to the car at Barcelona."

Lauda also says that he isn’t surprised that Ferrari have recovered so quickly after last year’s disappointments. “Their resurgence is deeply rooted in last season, in the good job done by (technical director) James Allison, in the restructuring of the team."

Both Lauda and Mercedes boss Toto Wolff believe that their drivers are at their peak, and that Bahrain signalled Rosberg’s return to form. He is currently 27 points adrift of championship leader Hamilton, but Wolff is adamant that the German will be back on the pace this weekend.

"Nico wouldn't be in Formula One as a multiple race winner and a challenger for the championship if he allowed himself to be destabilised after a few races,” Wolff says. "I fully expect him to come bouncing back. I don't know when it will happen, but he's always going to be there, no doubt."

Elsewhere, Red Bull and Toro Rosso are hoping for good news from Renault. The French power unit manufacturer’s director of operations Remi Taffin says that they have high hopes after making changes based on lessons learned from the first four races: “Barcelona is much more of a traditional circuit than the first four tracks we have visited so far this year. The layout flows a lot more, with high and medium speed corners rather than tight, slow hairpins and long straights.

“The three-week gap has given us an opportunity to look at all the information from the start of the season. We have been flat out to counter the issues encountered early on and we will have a modified spec of engine for this race that should give improved reliability and driveability.”

That should be a relief to Daniel Ricciardo, Daniil Kvyat, Max Verstappen and Carlos Sainz after their recent powertrain tribulations.

Williams are bringing not just updates but better knowledge of how to get the best out of their Pirelli tyres, which already helped to reduce the deficit to Mercedes and Ferrari in Bahrain. The Grove-based team will run test and development driver Susie Wolff in FP1 - her first appearance of the season.

Lotus have also heavily revamped their promising E23 Hybrid, which among other things will feature a Williams-like nose this weekend. And reflecting his performances in China and Bahrain, tester Jolyon Palmer will get another outing on Friday morning.

McLaren will be bringing more development to their MP4-30, but perhaps the most noticeable difference to the Honda-powered car will be in the livery department. The team have dropped the chrome colour scheme that has adorned their cars since 2006 and replaced it with a more “predatory” stealth-grey look. Local favourite Fernando Alonso will be hoping the new look brings him extra luck at a track he won on in 2006 and 2013.

The Circuit de Barcelona-Catalunya, at which the teams tested in February, places very high demands on tyres, especially the left front, because of its wide range of high-speed corners and rough asphalt. Thus tyre suppliers Pirelli are bringing their orange-marked hard and white-marked medium tyres this weekend.

“Spain is obviously one of the more familiar venues that we go to, as there has already been plenty of data gathered during testing,” says the Italian company’s motorsport director Paul Hembery.

“One of the things we have noticed so far is that this year Barcelona will once again be a front-limited circuit, from a tyre perspective. Last year, the increase in traction and torque from the cars meant that for the first time the race became a rear-limited event, with the useful life of the rear tyres dictating the pit stop strategy.

“Thanks to the improvements we made to the rear tyre construction for this year, we’re back to Barcelona being a front-limited circuit again. However, we do not expect this to mean that there will necessarily be more pit stops this year: last year the majority of competitors used a two-stop strategy and that will probably be the case again.

“The start of the European season traditionally means that many teams bring important upgrades, and it will be very interesting to see how these interact with our 2015 tyres.”

The 4.655-kilometre Barcelona track, a staple on the calendar since 1991, is largely unchanged since last year, though changes have been made to the kerbs at Turn 9 and Turn 15. A new CCTV camera has also been installed at Turn 3 - the site of Alonso’s unusual pre-season testing crash.

As in 2014, two DRS zones will be in operation over the weekend. The first has a detection point just after Turn 8 and an activation point after Turn 9, while the second has a detection point just ahead of Turn 16 with the activation point 157m along the pit straight.

The weather is expected to be dry, sunny and warm all weekend, with a high of 26 degrees Celsius on race day. Sunday’s Grand Prix will start at 1400 hours local time (1200 GMT) and will run over 66 laps or 307.104 kilometres (190.825 miles).